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2. A. Clearfield, Progress in Intercalation Research, W. Muller-Warmuty, R. Schollhorn (Eds.), Kluwer, Dordrecht, 1994, p. 223.
3. G. Alberti, C. Dionigi, S. Murcia-Mascarós, R. Vivani, Crystallography of Supramolecular Compounds, G. Tsoucaris (Ed.), Kluwer, Dordrecht, 1996, p. 143.
4. A. Clearfield, U. Costantino, Comprehensive Supramolecular Chemistry, G. Alberti, T. Bein (Eds.), Pergamon Press, New York, 1996.